He's saved the world a few times now, most recently in "The Avengers" when he flew in and out of a wormhole – but don't mention that word or he might hyperventilate.

Granted, living up to Marvel's current momentum at the multiplex is a lot of pressure, but "Iron Man 3" blasts off as the fun-filled, CGI-loaded blockbuster that moviegoers now demand of summer.

Certainly, writer/director Shane Black risks heading down that perilous path of superhero trilogies with more villains, more heroes, more storylines, more Hollywood clichés – even more endings.

What keeps the story grounded and the action soaring remains Robert Downey Jr. as Stark, a genius casting decision that's carried four films, and the screenplay by Black and Drew Pearce.

In "Iron Man 3," our hero is more vulnerable, cherishing his girl, Pepper Potts (Gwyneth Paltrow), and knowing that the villains are lining up to take him and his suit apart.

Most prominently, The Mandarin (Ben Kingsley) seems to enjoy killing innocent people and taunting the president. Meanwhile, Aldrich Killian (Guy Pearce), a scientist who Stark jilted way back before the turn of the millennium, is in control of a powerful technology called Extremis. He has the help of a wildcard: Maya Hansen (Rebecca Hall), who has a romantic past with Stark and the brains to challenge him.

Stark isn't too focused on any of it – until one attack hits close to home.

In this journey, Downey and Black (writer for "Lethal Weapon," "The Last Boy Scout" and "The Long Kiss Goodnight") succeed in returning Iron Man to his roots as the genius billionaire always ready to get his hands dirty and always quick with a one-liner. His response to a boy whose father abandoned him is priceless – showing Stark won't even treat kids with kid gloves.

Iron Man receives a hand from that kid sidekick and Iron Patriot – the new politically correct name for War Machine (Don Cheadle). More significantly, Paltrow's lovely Ms. Potts gets a chance to dirty her hands, giving the film a needed jolt.

Comic traditionalists might have the biggest complaints. The film borrows from a dozen "Iron Man" storylines while remaining irreverent to nearly all of them. One major change in a key villain will rankle many longtime fans, even if it proves entertaining to the average moviegoer.

The Neptune Beach resident sitting next to me in the preview owns every "Iron Man" title from the past 45 years. He was entertained and unbothered by the irreverence to the comics.

The film might remind moviegoers of other classics, including "Terminator 2" (the villains) and "Lethal Weapon" (the banter between Iron Man and Iron Patriot). Ms. Potts catches Stark flirting with her while working at the same time in a scene reminiscent of "Watchmen," and the ending might remind some viewers of "Titanic" – not in a good way.

As with many action films, questioning the plot is easy. Even if most decisions by the heroes and villains made sense, why didn't Iron Man just ring up the other Avengers for back up?

We're not supposed to think that much. Leave all the thinking to the billionaire genius in the suit. This time, more than ever, Stark shows his mettle by often working without the suit – the better to show Downey's face and hammer home the hero's vulnerability.

The overwrought emotional elements might be the film's biggest weakness.

However, "Iron Man 3" could have run into more trouble. The Mandarin looked like a one-note villain in the trailers and on paper, but Kingley's talents were not wasted.

The action set pieces deliver – especially the one involving Air Force One – but the film doesn't let the action run away with the story.

With all these moving parts, Iron Man continues to work with different directors, villains and sidekicks for one major reason: Downey's screen presence.

In delivering all those one-liners, another actor might come across as a jerk. Downey proves endearing.